Cascade reservoirs on the Tietê River (São Paulo, Brazil): impacts on water quality

• Grant number: 23/13367-1
• Support Opportunities: Regular Research Grants
• Duration: May 01, 2024 - April 30, 2026
• Field of knowledge: Engineering - Sanitary Engineering
• Principal Investigator: Marcelo Luiz Martins Pompêo
• Grantee: Marcelo Luiz Martins Pompêo
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Eduardo Vicente Pedrós ; Mathias Ahii Chia ; Sheila Cardoso da Silva ; Viviane Moschini Carlos

Abstract

This work aims to study in a comparative way six reservoirs cascading into the Tietê river (Barra Bonita, Bariri, Ibitinga, Promissão, Nova Avanhandava, Três Irmãos) (São Paulo, Brazil) through remote sensing techniques, using Sentinel images 2 (S2), worked on the SNAP software, both from the European Space Agency. It is expected to validate the algorithms to estimate the chlorophyll a (Chla) and phycocyanin (Phyco) concentrations and, indirectly, the cyanobacteria cells number (Cyano). SNAP's conc_chl automatic product will be validated for chlorophyll and the 665, 705 and 740 nm bands will be used to develop algorithms to validate Phyco. Thematic maps of Chla, Phyco, Cyano and the Trophic State Index will later be generated. Previous work has demonstrated the robustness of these estimates. The choice of these reservoirs is due to their strategic importance for the state, added to the fact that Barra Bonita, the first of them, is considered highly impacted by the waters of the Tietê River. S2 images with L1C level will be downloaded with dates of a maximum of three days difference from the collection date, undergoing a 20 m resampling, atmospheric correction (C2RCC) and cropping, keeping only the areas of interest. From 2024 to 2025, in situ sampling will take place in each reservoir, in profiles (temperature, dissolved oxygen, pH, electrical conductivity, nitrate and ammonium; Phyco, Chla and turbidity, with multiparameter probes). For each collection station, between April and September, integrated water samples will also be taken, up to the depth of the Secchi disk to determine the nitrogen and phosphorus series, Chla, Phyco, phytoplankton (qualitative and quantitative aspects), in at least five sampling stations per reservoir. It is also expected to produce manuscripts, in addition to promoting the training of human resources at all levels, including through international partnerships. (AU)